This application will continue to study the alterations which occur in the activity of the enzyme ornithine decarboxylase (ODC), thought to be the rate-limiting enzyme in the biosynthesis of the polyamines putrescine, spermidine and spermine, following the onset of diabetes mellitus. Previously we have observed that ODC activity in liver and kidney of diabetic rats is elevated early in the course of the disease and that this elevation can be prevented by insulin therapy. Liver ODC activity remains elevated for 3 weeks whereas kidney ODC activity becomes depressed after 1 week, remaining so for 3 weeks. To determine the mechanisms responsible for the altered ODC activity of the streptozotocin-induced diabetic state, we are studying the effects of altering hormones which are known to be abnormal in diabetes. These hormones include glucagon, adrenal steroids and androgens. These alterations will be performed by organ removal and hormonal replacements. In addition, the effects of fasting, a model analogous to diabetes in many of the metabolic disturbances which occur will be combined with diabetes to determine whether ODC activity is regulated similarly in both conditions. Treatment with mixtures of amino acids and with single amino acids will be tested in the diabetic animals to determine any role for these compounds in the regulation of ODC activity. In addition to studying the regulation of ODC activity in diabetic rats, we are measuring the levels of polyamines in the liver, kidney and urine of these animals. We will determine whether alterations in these compounds parallel changes in ODC activity with time. We will determine whether animals who are maintained with insulin therapy for several weeks to months have persistently altered polyamine levels in these tissues. If so, we will try to treat some animals with inhibitors of polyamine biosynthesis such as alpha-methyl ornithine. The effect of preventing the early changes in polyamine biosynthesis will be related to other metabolic parameters of diabetes including plasma glucose, ketone and lipid levels.